Description

The wcstol() and wcstoll() functions convert the initial portion of the wide
character string pointed to by nptr to long and long long representation, respectively.
They first decompose the input string into three parts:

a subject sequence interpreted as an integer represented in some radix determined by the value of base

a final wide character string of one or more unrecognised wide character codes, including the terminating null wide-character code of the input wide character string

They then attempt to convert the subject sequence to an integer, and
return the result.

If the value of base is 0, the expected form of the
subject sequence is that of a decimal constant, octal constant or hexadecimal
constant, any of which may be preceded by a `+' or `-'
sign. A decimal constant begins with a non-zero digit, and consists of a
sequence of decimal digits. An octal constant consists of the prefix `0'
optionally followed by a sequence of the digits `0' to `7' only.
A hexadecimal constant consists of the prefix `0x' or `0X' followed by
a sequence of the decimal digits and letters `a' (or `A') to
`f' (or `F') with values 10 to 15 respectively.

If the value of base is between 2 and 36, the expected
form of the subject sequence is a sequence of letters and digits
representing an integer with the radix specified by base, optionally preceded
by a `+' or `-' sign, but not including an integer suffix. The
letters from `a' (or `A') to `z' (or `Z') inclusive are
ascribed the values 10 to 35; only letters whose ascribed values are
less than that of base are permitted. If the value of base
is 16, the wide-character code representations of `0x' or `0X' may optionally precede
the sequence of letters and digits, following the sign if present.

The subject sequence is defined as the longest initial subsequence of the
input wide character string, starting with the first non-white-space wide-character code, that
is of the expected form. The subject sequence contains no wide-character codes
if the input wide character string is empty or consists entirely of white-space
wide-character code, or if the first non-white-space wide-character code is other than
a sign or a permissible letter or digit.

If the subject sequence has the expected form and the value of
base is 0, the sequence of wide-character codes starting with the first
digit is interpreted as an integer constant. If the subject sequence has
the expected form and the value of base is between 2 and
36, it is used as the base for conversion, ascribing to each
letter its value as given above. If the subject sequence begins with
a minus sign (-), the value resulting from the conversion is negated.
A pointer to the final wide character string is stored in the
object pointed to by endptr, provided that endptr is not a
null pointer.

If the subject sequence is empty or does not have the expected
form, no conversion is performed; the value of nptr is stored in
the object pointed to by endptr, provided that endptr is not
a null pointer.

These functions do not change the setting of errno if successful.

Since 0, {LONG_MIN} or {LLONG_MIN}, and {LONG_MAX} or {LLONG_MAX} are returned on
error and are also valid returns on success, an application wanting to
check for error situations should set errno to 0, call one of these
functions, then check errno.

The wstol() function is equivalent to wcstol().

The watol() function is equivalent to wstol(str,(wchar_t **)NULL, 10).

The watoll() function is the long-long (double long) version of watol().

The watoi() function is equivalent to (int)watol( ).

Return Values

Upon successful completion, these functions return the converted value, if any. If
no conversion could be performed, 0 is returned and errno may be
set to indicate the error. If the correct value is outside the
range of representable values, {LONG_MIN}, {LONG_MAX}, {LLONG_MIN}, or {LLONG_MAX} is returned (according to
the sign of the value), and errno is set to ERANGE.